package com.hmdp.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

@Component
public class RedisIdWorker {
    /**
     * 开始时间戳
     */
    private static final long BEGIN_TIMESTAMP = 1729262630L;
    /**
     * 序列号的位数
     */
    private static final int COUNT_BITS = 32;

    private StringRedisTemplate stringRedisTemplate;

    public RedisIdWorker(StringRedisTemplate stringRedisTemplate) {
        this.stringRedisTemplate = stringRedisTemplate;
    }



    public long nextId(String keyPrefix) {
        // 1.生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timestamp = nowSecond - BEGIN_TIMESTAMP;
        //获取当前秒数-开始秒数

        // 2.生成序列号
        //单调递增，需要用到redis递增长，所以注入StringRedisTemplate
        // 2.1.获取当前日期，精确到天
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        // 2.2.自增长
        long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);
        //里面拼接的是key，调用一次方法会自增一。没这个key就创建
        //increment方法就是一次自增1

        // 3.拼接并返回
        //这里第一次用到位运算，后面比特位现在都是0和count比特位比较，0|0=0 0|1=1；
        return timestamp << COUNT_BITS | count;


    }


}